VBA copy text from two word documents based on excel condition

I am trying to create a sub from excel that will open two existing word files one with standard text and another blank. These word documents and the excel workbook have the same string values as the bookmarks. If the corresponding cells adjacent to the excel bookmark are not blank I want to copy the standard text across to the other document. It just keeps crashing my excel, any ideas?

Sub BoQtoWord()
'Proof of concept to copy text from standard word doc to new word doc at same bookmark if condition met in excel workbook

Dim StdDoc As Word.Document
Dim NewDoc As Word.Document
Dim StdSpec As String
Dim NewSpec As String
Dim wb As Workbook
Set wb = ThisWorkbook
Dim ws As Worksheet
Set ws = ActiveSheet
Dim iRow As Integer
iRow = 6
Dim Bkm As String


'Get first doc
StdSpec = Application.GetOpenFilename(Title:="Please choose standard spec to open", _
FileFilter:="Word Files *.doc* (*.doc*),")
Set StdDoc = Documents.Open(StdSpec)

'Get second doc
NewSpec = Application.GetOpenFilename(Title:="Please choose new spec to open", _
FileFilter:="Word Files *.doc* (*.doc*),")
Set NewDoc = Documents.Open(NewSpec)


'Loop through workbooks and copy data from standard doc to new doc at same bookmark if values populated in column 4 and 7.

For Each ws In wb.Worksheets

    For iRow = 6 To 200
        Bkm = Cells(iRow, 9).Value
            If Cells(iRow, 9) <> "" And Cells(iRow, 4) <> "" Then

            Documents(StdDoc).Activate
            Selection.GoTo What:=wdGoToBookmark, Name:="Bkm"
            Selection.Copy

            Documents(NewDoc).Activate
            Selection.GoTo What:=wdGoToBookmark, Name:="Bkm"
            Selection.Paste

        End If
        iRow = 6 + 1

    Next iRow

Next



End Sub